Electromagnetic apparatus



April 23, 1940. A. wlNTHER ELECTROMAGNETIC APPARATUS Original Filed July 29, 1936 2 Sheets-Sheet 1 FIG I.

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April 23, 1940. A. wlNTHER ELECTROMAGNETIG APPARATUS Original Filed July 29, 1936 2 Sheets-Sheet 2 cre UNITED STATES PATENT OFFICE ELEcTnonnGNETxc ArrAnATUs Anthony Winther Original application 93,116. Divided This invention relates to improvements upon A states Patent 1,977,600,

dated October 16, 1934, reissued December 29, 5 193s as No. 20,225.

and the scope which will be indicated In the accompanying illustrated ments oi' of the application of in the following claims. drawings, in which are several of various possible embodithe invention,

is an end view on view illustrating another form of etic apparatus of the general class in Kenosha, Wis., signor 4t0 Martin P. Winther, as trustee,

Waukegan, Ill.

July 29, 1936, Serial No.

this application January 1938, Serial No. 186,138

(Cl. 18S-104) Reissue 20.225, wmie it sets form improvements in pole shapes, has in common with other old has the disadvantage-that above the relatively low sweep rates, the torque delivered from driving to drivenmember drops olf.

By means of the vpresent invention, the conditions are obtained in which there is continuous speed of the pole. sweep. y

Referring now more particularly to Figures l and 2, these show the invention as applied to an absorption dynamometer. Numeral I shows shaft I is a rotor terial, such as iron or steel peripheral teeth 5 with spaces 1- therebetween. Each tooth 5, by means of a central depression 9 is formed with two working faces or end areas II and which carries centrators or distorters.

Mounted around the shaft I is a swinging case I3 supported intorque or moment to a suitable measuring device. For the purpose of carrying away generated heat,

respectively. Between the channels I9 are peripheral walls 25 serving purposes to be described. Adjacent the inlets 23 and outlets 2l are cross passages I0 joining the respective sets of four passages I9 with said inlets or outlets,

peripheral points, except at said cross passages Il, the peripheral walls 25 completely separate the channels I9. Between the channels I9 is suitable source ofy serves to impress force on a scale balance or the like. It is to be understood that the water inlets 2l and outlets 2i have suitable flexible hose connections, so that the case I3 may freely swing to the degree required by the measuring apparatus with which the torque arm 3l contacts.

In view of the above, it will be seen that if the circuit is closed through the coil 29 the resulting excitation will result in a magnetic field being established of generally toric form around the coil 29 and along the general lines indicated by the arrows in Fig. 4. This induces two north and south magnetic poles axially arranged in the periphery of the case, as indicated. These north and south poles in the case will induce opposite polarities in the adjacent faces II of the teeth 5, the magnetic circuit passing through the case, and the various teeth 5. The teeth function as distorters of the magnetic field. All teeth at one end of the rotor 3 are of one polarity. Thus all adjacent teeth peripherally considered are of one polarity.

If the shaft I be rotated, it will be seen that the effect of the teeth 5, as their faces II pass a given point on the inner face of the case I3, is to concentrate the lines of flux from the adjacent areas into areas approximating the areas of the faces Ii of the teeth.

In the present improvement the successive concentrator poles are of the same polarity. Where the successive poles are of different polarities, and themselves cause in the inductor the magnetic field, said field must necessarily be reversed throughout as the successive reverse poles pass the given point. With the present apparatus, the lines of the magnetic circuit are never reversed in the Inductor. Furthermore, the magnetic field in the inductor is due as a whole to the coil in the inductor or in a stationary member, as in the drawings, and is not induced therein as a whole by adjacent and moving poles in the toothed member as heretofore, and the effect of the adjacent and moving poles is merely to distort without inducing the movement of this field completely or reversing it.

An advantage of electric dynamometers of the class shown in Figures 1 and 2 is that they are infinitely adjustable to various values of power. This is in contrast with the great difficulty encountered in adjusting the regulation of a load on such dynamometers as water brakes, rope brakes, and the like. Furthermore, the present type of dynamometer has a much lower cost than the old generator type. For example, electric dynamometers required to be'operated at very high speeds rnust have very expensive armatures, while in the case of the present invention, the rotor is nothing more than a small, solid toothed steel member.

It will at this time be seen that the walls 25 are iiatwise peripherally and are thus best adapted to accommodate therethrough the magnetic lines of force, and therebetween the circulating water. Thus the cooling water jacket is formed to carry the fiux. However, the flux path thus formed is only imperfect at best, and the advantage gained by the present scheme is that the fiux is unchanging through said imperfect path. Obviously. it would be difficult to pass rapidly changing flux through such an imperfect magnetic path, improved as it is.

I have carefully investigated the proper form of tooth to use to obtain the highest efficiency out of the new type of machine. 'To do this I have built a large number of rotors of varying tooth form. as to width, depth. spacing, tapering, etc., and in general can say that it is advantageous to taper the teeth from their bases to their faces, and to make their width such that the pole tooth end width will be between 25 and percent (say 35 percent as an average) of the total peripheral distance from the edge of one tooth to the corresponding edge of the next one. This can be stated in another way by saying that the width of an open space should be (for highest torque) about twice that of the width of a tooth.

The tooth depth may vary from one-fourth to twice the tooth width; it being best to make it about the latter for the reason that as little leakage as possible is desired between teeth. As disclosed in Patent 1,977,600 (Reissue 20,225), it is important to taper the tooth edges so as to effect fiux saturation at the tooth faces or ends.

In the case of Patent 1,977,600 (Reissue 20,225), it was shown that if the pole end areas were about thirty percent less than the sectional area of the pole which is needed to carry all the fiux including leakage flux which did not go through the end area, then highest efficiency of transmission was obtained. The same rule applies in the present circumstances, except that the areas to be considered are the superficial or radially disposed end areas of the teeth at either end portion of the rotor (exclusive of those at the other end), as compared to the cross-sectional area of the rotor through the waist Within the loop of the coil 29 including the areas of the depressed connecting portions 8. Thus the total of the superficial end areas of the teeth at one end of the rotor should be about thirty percent less than the central cross-sectional area of the rotor. This is for the same reason given in said patent, namely, that the cross-sectional area of the rotor needs to carry all of the fiux which is to pass out through the ends of the teeth, plus leakage fiux. In order to cause a maximum concentration at the tooth ends, the metal of the tooth ends should be worked at fiux saturation. Since there is about thirty percent leakage of flux aside from that which goes through the tooth end areas, it follows that, to saturate said tooth end areas with seventy percent of the flux, said areas must be thirty percent or so less than the rotor waist area. The rotor is in effect an axial pole, the waist of which must carry all flux, and the superficial end areas of the fiux-distorting teeth which carry only working flux, the remainder of the fiux being leakage flux.

In Fig. 3 is shown how in a single unit, the elements of the invention may be compounded. This figure is inserted to show that the new principle can be carried out by the use of more than two poles per tooth. This compound device is in effect several units in tandem and having several waist sections, one each of which waist sections is within a coil 29. On each side of each Waist section is enough superficial, radial tooth end area I I to fulfill the relationships above specified. As in Figs. 1-4 the areas of the depressed connecting portions 9 are included in considering the cross-sectional area of the waist. It will be understood that Fig. 3 is diagrammatic and not to scale.

An advantage of the invention is that the fiuxcarrying walls are arranged for efficient carriage of the fiux, and these are the parts in which the resulting eddy-currents are also generated. Thus these parts are arranged (1) for carriage of fiux, (2) for production of eddy-currents and (3) for the transmission of heat at a high rate ha 40 member which is forced and being generated. In the present invention, all three functions of efilcient flux carriage, work-heat conversion, and heat transmission are facilitated by the simple form of the apparatus described.

an alternative form of the stead of around the driven member 2 forced by the driving member. If desir in be applied to member 2 In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As many changes could be made in carrying `I claim:

1. In apparatus of the class described. a magnetic driving ving anaxisha magnetic I l l closed coil.

saturation at the radial ends 2. Apparatus of the class .described according to claim 1 in which the smooth-faced member is located exteriorly of the toothed member.

3. Apparatus of the class described according to claim l in which the smooth-faced member is located exteriorly of the toothed member and in which the electromagnet comprises a single 4. In apparatus of the class described, a magnetic driving member having an axis, a magnetic member which is forced and being coaxial, relatively movable and spaced faces on said members one of which faces is smooth and the other having teeth, the toothed member having a waist in a plane perpendicular to said axis, an electromagnet wound at said waist and carried toothed member having a waist and at least one at said waist and lying between the waist that the flux which actually emanates from said flux saturation at the radial ends of said teeth.

ANTHONY WINTHEI.

-named teeth eilects substantial 4l 

